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I am using web3.js 1.0.0-beta.36 to connect to the blockchain.

But unfortunately this code cannot connect to Metamask, if it has been enabled.

var metamask = false;
if (typeof web3 !== 'undefined') {
    web3 = new Web3(web3.currentProvider);
    metamask = true; 
    web3.eth.defaultAccount = web3.eth.accounts[0];
} else {
    web3 = new Web3(new
    Web3.providers.HttpProvider(infuraUrl));
    var address = web3.eth.accounts.create().address;
}
myContract = new web3.eth.Contract(abi,contractAddress);
myContract.methods.Register((Name,Id).send({},function(error,result){
    if (! error)
        console.log(result);
    else
        console.log(error);
});

When we run this program with Metamsk it displays this error:

Error: Returned error: Error: MetaMask Tx Signature: User denied transaction signature.

but when I mention a fixed address it works:

myContract.methods.Register((Name,Id).send({from: '0x...'},function(error,result){
        if (! error)
            console.log(result);
        else
            console.log(error);
    });

For some reasons I can't bring the address itself in the source code and I want it to get the address from Metamask. What should I do?

1

Eureka!!! (without special Archimedes style!)

Finally I found.

window.addEventListener('load', async () => {
    // Modern dapp browsers...
    if (window.ethereum) {
        window.web3 = new Web3(ethereum);
        try {
            await ethereum.enable();
            var accounts= await web3.eth.getAccounts();
            var option={from: accounts[0] };
            var myContract = new web3.eth.Contract(abi,contractAddress);
            myContract.methods.RegisterInstructor('11','Ali')
            .send(option,function(error,result){
                if (! error)
                    console.log(result);
                else
                    console.log(error);
            });
        } catch (error) {
            // User denied account access...
        }
    }
    // Legacy dapp browsers...
    else if (window.web3) {
        window.web3 = new Web3(web3.currentProvider);
        // Acccounts always exposed
        web3.eth.sendTransaction({/* ... */});
    }
    // Non-dapp browsers...
    else {
        console.log('Non-Ethereum browser detected. You should consider trying MetaMask!');
    }
});

This connects to Metamask properly. Main problem was that our browsers are supermodern!!!

Thanks to @Ismael, because of his help for 70% of solution.

  • can you help me with all your dependencies? can you share your entie codebase? I have metamask installed in chrome browser but i am always getting Non-Ethereum browser detected. You should consider trying MetaMask! error – cryptoKTM Aug 12 at 11:49
  • In newer versions you must try Metamask to enable at first: window.ethereum.enable(); – Alireza Zojaji Aug 13 at 15:02

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